MFRC630 TVDD current consumption(ITVDD) is too small

[toshihirosekiok]

Hello.

I use MFRC630 to communicate with Mifare card.

the datasheet shows IDD(TVDD) is typ.100mA and max.200mA.

AN11019 application notes shows IDD(TVDD) is depends on antenna impedance,

IDD(TVDD) is about 50mA When the impedance is 80OHM.

I measured my PCB total consumption.

MFRC630 stby --- 7.3mA

MFRC630 ACT(reading from Mifare card, its working fine) --- 26.75mA

current diff --- 19.45mA

I expected the current diff is IDD(modem on) 17mA + IDD(TVDD) 33mA = 50mA.

however measured current diff was 19.45mA.

(The Supply voltage is 3.3v , IDD(TVDD) will be 33mA)

I feel abnormal that the current is too little.
Can the MFRC 630 working by such a small current?

please help.

[weidong_sun]

Hello Toshihiro,

    >>the datasheet shows IDD(TVDD) is typ.100mA and max.200mA.

        At the time, TVDD=5V.  and didn't limit Min current.

   >>AN11019 application notes shows IDD(TVDD) is depends on antenna impedance,IDD(TVDD) is about 50mA When the impedance is 80OHM

       Antenna impedance should be 50 OHM, the bigger impedance , the smaller current.

   >>The Supply voltage is 3.3v , IDD(TVDD) will be 33mA

      I think the current is no problem, it should be less than that of TVDD=5V.

Hope above information can help you!

Have a great day,
TIC  weidong sun

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